Adhesive anchor

ABSTRACT

A construction anchor for mounting an object on a structure of masonry, concrete, metal or the like includes a metal anchoring portion and a plastic cap. The anchor is adapted to be inserted, metal end first, into a pre-drilled adhesive-filled hole. The cap has a flange that is larger than the hole diameter, so that the anchor may be inserted and seated in the hole at a consistent depth. When the adhesive has set, a screw or bolt is inserted through the plastic cap to engage the threads in an internal bore in the anchoring portion. The plastic cap serves not only to determine the depth of the anchor in the hole, but also to prevent adhesive and other material from entering the threaded interior of the anchor prior to use.

BACKGROUND OF THE INVENTION

1. Field of The Invention

The present invention relates to a construction anchor, and moreparticularly to a construction anchor comprising two parts receivable ina hole defined in structural materials such as masonry, concrete ormetal to secure an object or fixture to the surface of the structuralmaterial.

2. Description of the Prior Art

Construction anchors of the above-mentioned general type are known inthe art. Typically, such anchors are made of metal in a substantiallycylindrical shape. They also include a longitudinal threaded bore inwhich an appropriately sized headed bolt may be disposed.

In use, construction anchors of this general type are adhesively bondedinto holes defined in masonry, concrete and similar materials. When thecement or adhesive, perhaps an epoxy, has sufficiently hardened orcured, an object may be mounted on the masonry surface by means of abolt driven into the threaded bore of the construction anchor.

In the prior art, it has proven to be difficult to set the constructionanchors to a uniform depth in the holes drilled in the masonry. Inaddition, as the cement or adhesive is introduced into the hole beforethe construction anchor, it has a tendency to be compressed out of thehole as the construction anchor is being introduced thereinto, and toextrude or seep into the threaded bore, where it may harden and preventa bolt from being readily disposed therein.

The present invention is a construction anchor representing a solutionto these deficiencies of the prior art.

SUMMARY OF THE INVENTION

The present invention is a construction anchor having a two-piececonstruction including a generally cylindrical anchoring portion ontowhich a cap is snap-fit. The cap covers an axial threaded bore, adaptedto receive a bolt, in the anchoring portion. The ultimate purpose of theconstruction anchor is to securely retain an object against the surfaceof a structural material such as masonry, concrete or metal.

The cap has a two-fold purpose. It is first provided with an annularflange, intended to sit on the periphery of the hole into which theconstruction element is to be inserted, so that the construction anchormay be set into the hole at a predetermined depth. The cap also preventsthe adhesive used to bond the construction anchor within the hole fromentering the internal threads or cavity of the anchoring portion.

The anchoring portion may also have a series of annular grooves defininglobes at its lower end, that is, the innermost end with reference to thehole into which the construction anchor is to be inserted, to provide aninterconnection with the adhesive. The upper end of the anchoringportion may have longitudinal splines which serve to prevent rotation ofthe construction anchor as a bolt is threadingly connected thereto.

The cap may have a plurality of longitudinal raised ridges on its outersurface below the annular flange, so that it may fit snugly within anappropriately dimensioned hole, yet may also permit the adhesive placedin the hole prior to the construction anchor to extrude or seep outwardbetween the raised ridges as the anchor is inserted therein to firmlyhold it along its entire length within the hole.

The anchor of the invention is particularly effective in maintainingsecure holding power even when subjected to dynamic cyclical loading orvibration. The bolt is installed with an applied initial stress whichtends to elongate the bolt and thus overcome "creep" at peak dynamiccyclical loading or the effects of vibration induced by wind or otherforces.

The present invention will be described in more complete detail belowwith frequent reference being made to the accompanying figures, whichmay be identified as follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of the anchoring portion of the constructionanchor.

FIG. 2 is a view of an end of the anchoring portion having a threadedbore.

FIG. 3 is a side view of the cap of the construction anchor.

FIG. 4 is a cross-section of the cap of the construction anchor takenalong the longitudinal axis thereof and viewed from the side.

FIG. 5 is a view of the top of the cap of the construction anchor.

FIG. 6 is a view of the cap from below.

FIGS. 7 and 8 illustrate the use of the construction anchor of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 prints a side view of the anchoring portion 10 of theconstruction anchor of the present invention. The lower end of theanchoring portion 10 may be provided with at least one major annulargroove 12, and with at least one minor annular groove 14. The majorannular grooves 12 are deeper and wider than the minor annular grooves14. These grooves 12,14 provide an interconnection between the anchoringportion 10 and the adhesive used to hold it within a hole in masonry, sothat it may resist extraction therefrom.

The upper end of the anchoring portion 10 has a plurality oflongitudinal splines 16. These also provide an interconnection betweenthe anchoring portion 10 and the adhesive, so that the anchoring portion10 may resist rotation within a hole when a bolt is being threadinglyconnected thereto.

At the very upper end of the anchoring portion 10 is a narrowedextension 18 having an annular groove 20 thereabout. Annular groove 20provides a means by which the cap, to be described below, may beattached and provide a tight seal to the anchoring portion 10. Athreaded bore 22 is provided in the upper end of the anchoring portion10, as suggested by the dashed lines in FIG 1.

FIG. 2 is a view of the upper end of the anchoring portion 10 showingthe threaded bore 22, which is centered in the narrowed extension 18 ofthe anchoring portion 10. Longitudinal splines 16, extending from belowto beyond the level of the unsplined section 24 of the anchoring portion10, are arranged about the circumference of its surface.

The anchoring portion 10 of the construction anchor is preferably madeof metal, such as, for example, zinc-plated steel.

FIG. 3 presents a side view of the cap 30 of the construction anchor.The cap 30 includes an annular flange 32 extending from and forming acontinuation of its upper surface 34. Below the annular flange 32, onthe outer surface 36 of the cap 30, are a plurality of longitudinalraised ridges 38, whose function will be illustrated below.

FIG. 4 is a cross section of the cap 30 shown in FIG. 3. For presentpurposes, it is important to note that the bottom of the cap 30 is open,and is provided with an inwardly radial flange 40 at the base of itsinner surface 42. Flange 40 snappingly fits into annular groove 20 onthe narrowed extension 18 of the anchoring portion 10 to join the cap 30thereto in a fluidtight seal.

The upper surface 34 of the cap 30 is closed, but is provided with meansin a recessed central area 44 enabling central area 44 to be puncturedby an instrument, such as the threaded end of a bolt.

In this regard, FIG. 5 presents a view of the top of the cap 30. Theupper surface 34 is provided with a recessed central area 44 having amolded, asterisk-shaped series of cuts 46. The cuts 46 represent weakpoints enabling a threaded end of a bolt to be pushed through therecessed central area 44, after the construction anchor has beenadhesively bonded in a hole drilled in masonry or the like, and whensuch a bolt is to be disposed within threaded bore 22 to mount anobject. The cap 30, for this reason, is ideally fashioned from a plasticmaterial, such as polyethylene.

FIG. 6 is a view of the cap 30 from below, and shows flange 40 extendingradially about the lower inside edge thereof. Annular flange 32 extendsradially beyond the longitudinal raised ridges 38, as may clearly benoted. The construction anchor of the present invention is ideallyinserted in a hole of radius slightly smaller than that represented bythe maximum radial extent of longitudinal raised ridges 38, so that theconstruction anchor may be inserted into such hole until the annularflange 32 comes to rest against the edges thereof and prevents anyfurther insertion.

The use of the present construction anchor is shown in FIGS. 7 and 8.The construction anchor 50 is a two-piece construction comprising thecap 30 and the anchoring portion 10, which snappingly fit togetherthrough the cooperation of annular groove 20 extending about narrowedextension 18 of the anchoring portion 10 and the radial flange 40 on theinner surface 42 of cap 30.

In practice, a hole 52 of radius slightly smaller than that representedby the maximum radial extent of longitudinal raised ridges 38 is drilledinto a concrete wall and the hole 52 is cleaned of debris by brush orair pressure. An injection gun is then used to inject a constructionadhesive, such as epoxy 54, into the hole 52. Thereafter, theconstruction anchor 50 of the present invention is inserted into thehole 52 with the annular flange 32 on cap 30 positioning theconstruction anchor 50 at a predetermined depth into the hole 52. As theconstruction anchor 50 is inserted into the hole 52, it becomes immersedin the epoxy 54 previously injected thereinto. The cap 30 prevents theepoxy 54 from entering into the threaded bore 22 in the anchoringportion 10, and also seats the construction anchor 50 when the annularflange 32 engages the concrete wall adjacent to the hole 52.

Referring to FIG. 8, a fixture 56 to be attached to the wall is thenpositioned over the construction anchor 50 and a mounting bolt 58 isinserted through the a pre-drilled hole in fixture 56 and through themolded, asterisk-shaped series of cuts 46 in the recessed central area44 on the upper surface 34 of the cap 30. The bolt 58 is thenthreadingly engaged into the threaded bore 22 of the anchoring portion10, and firmly tightened to secure fixture 56 to the wall. Thetightening of the bolt 58 applies an initial stress which tends toelongate the bolt between the head and the connection to the anchor,with the attendant operational advantages mentioned above. Theelongation of the bolt is exaggerated in FIG. 8 to illustrate theprinciple.

Modifications to the invention described above would be obvious to thoseskilled in the art, and would not bring the invention so modified beyondthe scope of the appended claims.

What is claimed is:
 1. A construction anchor for retaining an objectagainst. .,.!. a structure of masonry, concrete, metal or the like, saidconstruction anchor, in use, being secured within a hole defined in saidstructure, comprising:a cylindrical anchoring portion having a threadedaxial bore extending partially through said anchoring portion from oneend thereof; and a cap adapted to be snap-fit over said end to coversaid threaded axial bore, said cap having an annular flange seatable onthe periphery of said hole, so that said construction anchor may be setinto said hole at a predetermined and consistent depth.
 2. Aconstruction anchor as claimed in claim 1 wherein said cylindricalanchoring portion is made of metal.
 3. A construction anchor as claimedin claim 2 wherein said metal is zinc-plated steel.
 4. A constructionanchor as chimed in claim 1 wherein said cap is of a plastic material.5. A construction anchor as claimed in claim 4 wherein said plasticmaterial is polyethylene.
 6. A construction anchor as claimed in claim 1wherein said cylindrical anchoring portion has at least one firstannular groove.
 7. A construction anchor as claimed in claim 6 whereinsaid cylindrical anchoring portion has at least one second annulargroove, said second annular groove being narrower in a longitudinaldirection along said cylindrical anchoring portion than said firstannular groove.
 8. A construction anchor as claimed in claim 1 whereinsaid cylindrical anchoring portion has a plurality of annular grooves.9. A construction anchor as claimed in claim 8 wherein said plurality ofannular grooves includes at least one first annular groove and at leastone second annular groove, said first annular groove being deeper thansa annular groove.
 10. A construction anchor as claimed in claim 1wherein said cylindrical anchoring portion has a plurality oflongitudinal splines.
 11. A construction anchor as claimed in claim 1wherein said end of said cylindrical anchoring portion having saidthreaded axial bore has a narrowed extension with an annular grooveextending thereabout, and said cap has an annular flange extending aboutthe base of its inner surface, so that said cap may be snap-fit ontosaid cylindrical anchoring portion.
 12. A construction anchor as claimedin claim 1 wherein said cap has an outer surface, said outer surfacehaving a plurality or longitudinal raised ridges for disposing saidconstruction anchor evenly within said hole in said structure.
 13. Aconstruction anchor as claimed in claim 1 wherein said cap has an uppersurface, said annular flange being an extension or said upper surface,said upper surface being puncturable by the threaded end of a bolt to besecured within said construction anchor. .Iadd.
 14. A constructionanchor for retaining an object against a structure of masonry, concrete,metal or the like, said construction anchor, in use, being securedwithin a hole defined in said structure, said construction anchorcomprising a cylindrical member having a first end, a second end and alongitudinal axis, a threaded axial bore extending partiallytherethrough from said first end, and at least one first annular groovearound said second end, thereby providing a lobe in said cylindricalmember at said second end, said lobe having a surface oriented obliquelywith respect to said longitudinal axis, said threaded axial boreterminating within said cylindrical member short of said at least onefirst annular groove and a cap tightly fitted upon said first end tocover said threaded axial bore..Iaddend..Iadd.
 15. A construction anchoras claimed in claim 14 wherein said cylindrical member is made ofmetal..Iaddend..Iadd.16. A construction anchor as claimed in claim 15wherein said metal is zinc-plated steel..Iaddend..Iadd.17. Aconstruction anchor as claimed in claim 14 wherein said cylindricalmember has at least one second annular groove, said at least one secondannular groove being narrower in a longitudinal direction along saidcylindrical member than said at least one first annulargroove..Iaddend..Iadd.18. A construction anchor as claimed in claim 17wherein said at least one first annular groove is deeper than said atleast one second annular groove..Iaddend..Iadd.19. A construction anchoras claimed in claim 14 wherein said cylindrical anchoring portion has atleast one longitudinal spline at said first end..Iaddend..Iadd.20. Aconstruction anchor as claimed in claim 14 wherein said cylindricalanchoring portion has a plurality of longitudinal splines at said firstend..Iaddend..Iadd.21. A construction anchor as claimed in claim 14wherein said at least one first annular groove is a plurality of firstannular grooves, each of said plurality being separated from oneadjacent thereto by a lobe..Iaddend..Iadd.22. A construction anchor asclaimed in claim 14 wherein said cap is of a plasticmaterial..Iaddend..Iadd.23. A construction anchor as claimed in claim 22wherein said plastic material is polyethylene..Iaddend..Iadd.24. Aconstruction anchor as claimed in claim 14 wherein said first end ofsaid cylindrical anchoring portion having said threaded axial bore has anarrowed extension with an annular groove extending thereabout, and saidcap has an annular flange extending about the base of its inner surface,so that said cap may be snap-fit onto said cylindrical anchoringportion..Iaddend..Iadd.25. A construction anchor as claimed in claim 14wherein said gap has an outer surface, said outer surface having aplurality of longitudinal raised ridges for disposing said constructionanchor evenly within said hole in said structure, said longitudinalraised ridges centering and suspending said construction anchor in saidhole..Iaddend..Iadd.26. A construction anchor as claimed in claim 14wherein said cap has an upper surface, said upper surface beingpuncturable by the threaded end of a bolt to be secured within saidconstruction anchor, said upper surface protecting said threaded axialbore from dirt..Iaddend..Iadd.27. A construction anchor as claimed inclaim 26 wherein said upper surface of said cap and said threaded axialbore of said cylindrical anchoring portion are separated by a distanceproviding a stretch zone for a bolt..Iaddend..Iadd.28. A constructionanchor as claimed in claim 14 wherein said cap has an annular flangeseatable on the periphery of said hole, so that said construction anchormay be set into said hole at a predetermined and consistentdepth..Iaddend.